Intact Levator Ani Muscle Research Articles

Associations of Maternal Complaints to Levator Ani Muscle Trauma within 9 Months after Vaginal Birth: A Prospective Observational Cohort Study.

Introduction Pelvic floor trauma in the form of partial or complete avulsions of the levator ani muscle (LAM) affects 6-42% of women after vaginal birth and can cause tremendous long-term morbidity. Many studies assessed morphological pelvic floor trauma after childbirth but lacked to evaluate women's associated short-term complaints. A proper assessment of trauma and subjective complaints after birth could help to assess possible associations between them and their relevance to women's daily life. Therefore, we aimed to assess women's complaints within the first months after birth in association to their LAM trauma. Materials and Methods Between 3/2017 and 4/2019, we prospectively evaluated vaginal births of 212 primiparous women with singletons in vertex presentation ≥ 36 + 0 gestational weeks for levator ani muscle (LAM) trauma by translabial ultrasound, for pelvic organ prolapse by clinical examination, and for urogynecological complaints using questionnaires 1-4 days (P1), 6-10 weeks (P2), and 6-9 months (P3) after birth. The questionnaires were self-designed but oriented to and modified from validated questionnaires. Women's complaints were evaluated for P1-P3 according to their LAM trauma state. Results At P1, 67% of women showed an intact LAM, whereas 14.6% presented a hematoma, 6.6% a partial avulsion (PAV), and 11.8% a complete avulsion (CAV). At P2, 75.9% showed an intact LAM, 9.9% a PAV, and 14.2% a CAV. At P3, 72.9% of women with a LAM trauma in P1 and/or P2 were assessed with 21.6% being intact and 39.2% having a PAV and CAV, respectively. Obstetrical and baseline characteristics differed slightly between the groups. When comparing the time before and during pregnancy with the time after childbirth, birth itself affected women's complaints in all LAM state groups, but the presence of a LAM trauma, especially a CAV, had more negative effects. Conclusions Vaginal birth changes the anatomical structure of the maternal birth canal and genital tract, and it alters women's perceptions and body function. In our study, LAM trauma did not change these effects tremendously within the first months. Therefore, other maternal, fetal, and obstetrical factors need consideration for the explanation of maternal complaints, in addition to long-term effects of trauma and dysfunction of the LAM and other birth canal structures.

2D pelvic floor ultrasound imaging in identifying levator ani muscle trauma agrees highly with 4D ultrasound imaging.

The objective was to evaluate the agreement between 2D and 4D translabial ultrasound (TLUS) technique in showing levator ani muscle (LAM) states after vaginal birth. In a prospective observational cohort study between March 2017 and April 2019 we evaluated LAM states (intact, hematoma, partial, complete avulsion) of primiparous women having given birth vaginally with singletons in vertex presentation ≥ 36+0 gestational weeks by using 2D and 4D TLUS within 1-4 days postpartum (assessment A1) and again 6-10 weeks postpartum (assessment A2). Cohen's Kappa analysis was performed for each side separately to evaluate the test agreement between the two ultrasound techniques at every assessment period. A total of 224 women participated at A1 and 213 at A2. The agreement between the two ultrasound techniques was good to very good at A1 (Cohen`s kappa right-sided 0.78, left-sided 0.82) and very good at A2 (Cohen`s kappa both sides 0.88). The agreement was best when assessing an intact LAM or a complete avulsion (Cohen`s kappa between 0.78-0.92 for complete avulsions). The comparison between 2D and 4D TLUS showed a good to very good agreement in LAM trauma immediately after birth as well as 6-10 weeks postpartum. Therefore, 2D ultrasound could also be a valuable method for demonstrating a LAM abnormality and could be used in settings where 3D/4D ultrasound equipment is not available.

Natural history of levator ani muscle avulsion 4 years following childbirth.

The primary aim was to evaluate prospectively the natural history of levator ani muscle (LAM) avulsion 4 years following first delivery and its correlation with signs and symptoms of pelvic floor dysfunction (PFD). The secondary aim was to investigate the effect of a second vaginal delivery on the incidence of LAM avulsion and PFD. This was a prospective longitudinal study of nulliparous women recruited antenatally, who were assessed at 36 weeks' gestation and 3 months, 1 year and 4 years postpartum for signs and symptoms of PFD and presence of LAM avulsion. Pelvic floor muscle strength was assessed by digital palpation, and pelvic organ prolapse (POP) was assessed using the POP quantification (POP-Q) system. Validated questionnaires were used to evaluate urinary, bowel and sexual function and symptoms of POP. Transperineal ultrasound was performed to assess LAM integrity and hiatal biometry. Differences in signs and symptoms of PFD over time were evaluated using a linear mixed model, separately in women who had had one delivery and in those who had two or more deliveries during the study period. Of 269 women recruited, 147 (55%) attended the 4-year follow-up and were examined at a mean interval of 3.8 ± 0.4 years after their first delivery. Of these, 74 (50%) had a subsequent delivery. The prevalence of LAM avulsion 4 years after a first vaginal delivery was 13%, with no difference between women who had one and those who had two or more vaginal deliveries. Women with an intact LAM and one or more deliveries showed no change in signs and symptoms of PFD at 4 years compared with the previous assessments. Of women with one vaginal delivery who were diagnosed with LAM avulsion 3 months or 1 year postpartum, those in whom the LAM avulsion was no longer evident at 4 years (42%) showed worsening of POP-Q measurements, whereas those with persistent LAM avulsion (58%) showed significant worsening in pelvic floor muscle strength and hiatal area on ultrasound. After a second vaginal delivery, no new avulsions were diagnosed, however, previous LAM avulsion became more extensive in 44% of women and hiatal area increased in women with persistent LAM avulsion. The first vaginal delivery carries the greatest risk for LAM avulsion, with impact on signs of PFD 4 years later. A second vaginal delivery could result in deterioration of LAM avulsion, but no new avulsions were found. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Levator ani muscle injury and risk for urinary and fecal incontinence in parous women from a normal population, a cross-sectional study.

To study possible associations between levator ani muscle (LAM) injury and urinary incontinence (UI) and fecal incontinence (FI) and possible associations between bladder neck descent (BND), urethral funneling, and UI. A cross-sectional study of 608 women with first delivery in 1990 to 1997 assessed in 2013 to 2014. The Urinary Distress Inventory (UDI-6) and Colorectal Anal Distress Inventory (CRADI-8) were used to quantify symptoms (range, 0-100). The proportion of women with UI and FI was calculated. LAM injury, BND ≥25 mm, and funneling were diagnosed with transperineal ultrasound. Women with LAM injury, BND, and urethral funneling were compared to those without, using the Mann-Whitney U test (symptom scores) and multiple logistic regression analysis (UI and FI). Four-hundred ninety-three (81%) women had intact LAM and 113 (19%) had LAM injury. They had similar median (range) UDI-6 score 8.3 (0-75) vs 4.2 (0-62.5), P = .35, and CRADI-8 score 6.3 (0-78.1) vs 6.3 (0-62.5), P = .90. Three hundred eleven out of six hundred (52%) women had UI and 65 of 594 (11%) had FI. This was similar for women with intact vs injured LAM; UI 53% vs 49%, P = .67; FI 11% vs 12%, P = .44 and with and without BND; stress UI 42% vs 42%, P = .93; urge UI 29% vs 35%, P = .34. Stress UI was more common in women with urethral funneling (50% vs 40%), odds ratio 1.56 (95% confidence interval: 1.03-2.37), P = .04. We found no associations between LAM injury and symptoms of UI and FI 15 to 24 years after the first delivery, but urethral funneling was associated with stress UI.

Translabial Ultrasound Combined With Magnetic Resonance Imaging Assessing the Distensibility of Levator Ani Muscle With Unilateral High-Grade Tears.

It is hypothesized that unilateral high-grade tears damage levator ani muscle (LAM) integrity and increase LAM distensibility. This study aimed to investigate how a unilateral high-grade tear caused overdistension of LAM and whether tear positions affect the degree of distension. A total of 209 women were screened by translabial ultrasonography. Then, 18 nulliparous women with an intact LAM and 26 postpartum women with unilateral levator ani defects were recruited. The anteroposterior diameter (AP), coronal diameter (LR), and hiatal area (HA) of the minimum levator hiatus were recorded and compared for assessing the distensibility. All 44 subjects underwent magnetic resonance imaging for the diagnosis of levator ani defect and detection of tear positions. Within the software, 3-dimensional pelvic models were developed from magnetic resonance imaging scans for the direct visualization and measurements. Of the 26 postpartum women, 15 were diagnosed with unilateral high-grade tear (caudad in 9, cephalad in 6). The △AP, △LR, and △HA (Valsalva-rest) values of women with a unilateral high-grade tear were significantly larger than those of women with an intact LAM (P < 0.05). The △AP, △LR, and △HA (Valsalva-rest) values of cephalad tears were larger than those of women with caudad tears (P < 0.05). A unilateral high-grade tear caused the overdistension of LAM. It was validated that cephalad tears caused higher degree of LAM distension than caudad tears.

Association between pelvic floor muscle trauma and contraction in parous women from a general population.

To study possible associations between pelvic floor muscle contraction, levator ani muscle (LAM) trauma and/or pelvic organ prolapse (POP) ≥ Stage 2 in parous women recruited from a general population. This was a secondary analysis of data from a cross-sectional study of 608 parous women from a general population examined using the POP quantification system (POP-Q) and three-dimensional/four-dimensional transperineal ultrasound for identification of LAM macrotrauma (avulsion) and microtrauma (distension of levator hiatal area > 75th percentile on Valsalva maneuver). Muscle contraction was assessed using the modified Oxford scale (MOS), perineometry and ultrasound measurement of proportional change of anteroposterior hiatal diameter and levator hiatal area at rest and on pelvic floor muscle contraction. The Mann-Whitney U-test was used to study associations between pelvic floor muscle contraction, LAM trauma and POP. Women with macrotrauma (n = 113) had significantly weaker median pelvic floor muscle contraction, as measured using MOS and perineometry, than did women with an intact LAM (n = 493) (contraction strength was 1.5 (range, 0.0-5.0) vs 3.5 (range, 0.0-5.0) on MOS, and vaginal squeeze pressure was 15.0 (range, 0.0-78.0) cmH2 O vs 28.0 (range, 0.0-129.0) cmH2 O on perineometry; P < 0.001). This was also demonstrated by ultrasound measurement, with a proportional change in hiatal area of 19.9% (range, 4.1-48.0%) vs 34.0% (range, 0.0-64.0%) (P < 0.001) and proportional change in anteroposterior diameter of 16.2% (range, -5.7 to 42.6%) vs 26.0% (range, -3.4 to 49.4%) (P < 0.001). No statistically significant difference between women with (n = 65), and those without (n = 378), microtrauma was found after excluding women with macrotrauma. Women with POP had weaker muscle contraction than those without; in those with POP-Q ≥ 2 (n = 275) compared with those with POP-Q < 2 (n = 333), muscle contraction strength was 3.0 (range, 0.0-5.0) vs 3.5 (range, 0.0-5.0) on MOS, vaginal squeeze pressure was 21.0 (range, 0.0-98.0) cmH2 O vs 28.0 (range, 3.0-129.0) cmH2 O on perineometry, proportional change in hiatal area was 29.6% (range, 0.0-60.9%) vs 33.8% (range, 0.0-64.4%) and proportional change in anteroposterior diameter was 22.8% (range, -5.7 to 49.4%) vs 25.7% (range, -3.4 to 49.4%) (P < 0.001 for all). LAM macrotrauma was associated with weaker pelvic floor muscle contraction measured using palpation, perineometry and ultrasound. Women with POP had weaker contraction than did women without POP. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Preliminary Outcome of Individualized Abdominoperineal Excision for Locally Advanced Low Rectal Cancer.

Background:The introduction of individualized abdominoperineal excision (APE) may minimize operative trauma and reduce the rate of complications. The purpose of this study was to evaluate the safety and efficacy of individualized APE for low rectal cancer.Methods:Fifty-six patients who underwent individualized APE from June 2011 to June 2015 were evaluated retrospectively in Beijing Chaoyang Hospital, Capital Medical University. The main outcome measures were circumferential resection margin (CRM) involvement, intraoperative perforation, postoperative complications, and local recurrence. Statistical analysis was performed using SPSS version 16.0.Results:Fifty (89%) patients received preoperative chemoradiotherapy: 51 (91%) patients were treated with the sacrococcyx preserved; 27 (48%) patients with the levator ani muscle partially preserved bilaterally; 20 (36%) patients with the levator ani muscle partially preserved unilaterally and the muscle on the opposite side totally preserved; 7 (13%) patients with intact levator ani muscle and part of the ischioanal fat bilaterally dissected; and 2 (4%) patients with part of the ischioanal fat and intact lavator ani muscle dissected unilaterally and the muscle on the opposite side partially preserved. The most common complications included sexual dysfunction (12%), perineal wound complications (13%), urinary retention (7%), and chronic perineal pain (5%). A positive CRM was demonstrated in 3 (5%) patients, and intraoperative perforations occurred in 2 (4%) patients. On multiple logistic regression analysis, longer operative time (P = 0.032) and more intraoperative blood loss (P = 0.006) were significantly associated with perineal procedure-related complications. The local recurrence was 4% at a median follow-up of 53 months (range: 30–74 months).Conclusion:With preoperative chemoradiotherapy, individualized APE may be a relatively safe and feasible approach for low rectal cancer with acceptable oncological outcomes.

Is bladder neck and urethral mobility associated with urinary incontinence and mode of delivery 4 years after childbirth?

To study changes in bladder neck, urethral mobility and urinary incontinence (UI) from pregnancy to 4 years postpartum and demonstrate any association to mode of delivery or presence of levator ani muscle (LAM) injury. Secondly, we aimed to correlate bladder neck and urethral mobility to UI symptoms. Prospective study of 180 women, recruited in their first pregnancy and followed up 1 and/or 4 years postpartum. UI symptoms were assessed with a validated questionnaire. All underwent 4D transperineal ultrasound to assess LAM injury, bladder neck descent (BND), retrovesical angle at Valsalva (RVA), and urethral rotation between rest and Valsalva. A mixed model compared changes over time, different delivery modes, and women with and without LAM injury. Spearman's rank correlation tested the correlation of BND, RVA, and urethral rotation to UI symptoms. BND, RVA, and urethral rotation all increased following delivery. From 1 to 4 years postpartum, a larger increase in BND was found for women delivered vaginally with LAM injury, compared to women with intact LAM (P = 0.02) and women with cesarean section (P = 0.046). One year postpartum, BND and RVA correlated to UI symptoms, rs = 0.22, P = 0.01. Four years postpartum, RVA correlated to UI symptoms, rs = 0.19, P = 0.02. Although bladder neck and urethral mobility increased from pregnancy to 4 years postpartum irrespective of delivery mode, women with LAM injury had larger increase in BND, suggesting that this is important in the pathogenesis of bladder neck mobility and could lead to pelvic floor dysfunction in the long term.

Pelvic floor dysfunction after levator trauma 1-year postpartum: a prospective case-control study.

The aim of this study was to evaluate pelvic floor dysfunction and anatomical signs of pelvic organ prolapse (POP) in patients with levator ani muscle (LAM) trauma compared with patients with an intact LAM 1 year postpartum. In a prospective case-control study, primiparous women after vaginal delivery, with LAM trauma diagnosed on 3D ultrasound, were included in the case group. Controls consisted of patients who fulfilled the same inclusion criteria but had an intact levator. All women were investigated 1 year postpartum in respect of bladder, bowel, prolapse, and sexual function using the Australian Pelvic Floor Questionnaire. POP was assessed according to the Pelvic Organ Prolapse Quantification (POP-Q) system and pelvic floor muscle strength using the Oxford Grading Scale. Forty patients were included: 20 with and 20 without levator trauma. Urinary symptoms were significantly more frequent in women with LAM trauma compared with controls (p = 0.01). The two groups were comparable in respect of bowel, sexual, and prolapse symptoms (p = 0.24, p = 0.60, p = 0.99 respectively). Unlike POP stages II and III, POP stage I was significantly more common in LAM trauma patients (n = 19, 95 %) than in controls (n = 10, 50 %) (p =0.003). A positive association was noted between POP stage I and LAM trauma (RR = 7.2). The involvement of multiple compartments was significantly more frequent in cases than in controls (p = 0.003). Except for urinary symptoms, LAM trauma was asymptomatic in nearly all patients 1 year postpartum. However, POP stage I involving multiple compartments occurred more frequently in LAM trauma patients than in controls.

Agreement and reliability of pelvic floor measurements during contraction using three‐dimensional pelvic floor ultrasound and virtual reality

Virtual reality is a novel method of visualizing ultrasound data with the perception of depth and offers possibilities for measuring non-planar structures. The levator ani hiatus has both convex and concave aspects. The aim of this study was to compare levator ani hiatus volume measurements obtained with conventional three-dimensional (3D) ultrasound and with a virtual reality measurement technique and to establish their reliability and agreement. 100 symptomatic patients visiting a tertiary pelvic floor clinic with a normal intact levator ani muscle diagnosed on translabial ultrasound were selected. Datasets were analyzed using a rendered volume with a slice thickness of 1.5 cm at the level of minimal hiatal dimensions during contraction. The levator area (in cm(2)) was measured and multiplied by 1.5 to get the levator ani hiatus volume in conventional 3D ultrasound (in cm(3)). Levator ani hiatus volume measurements were then measured semi-automatically in virtual reality (cm(3) ) using a segmentation algorithm. An intra- and interobserver analysis of reliability and agreement was performed in 20 randomly chosen patients. The mean difference between levator ani hiatus volume measurements performed using conventional 3D ultrasound and virtual reality was 0.10 (95% CI, - 0.15 to 0.35) cm(3). The intraclass correlation coefficient (ICC) comparing conventional 3D ultrasound with virtual reality measurements was > 0.96. Intra- and interobserver ICCs for conventional 3D ultrasound measurements were > 0.94 and for virtual reality measurements were > 0.97, indicating good reliability for both. Levator ani hiatus volume measurements performed using virtual reality were reliable and the results were similar to those obtained with conventional 3D ultrasonography.

Effect of contractions in vitro on glycogen content and glycogen synthetase activity in muscle.

AbstractThe influence of contraction on the content of glycogen in muscle as well as on the activity of the glycogen synthetase enzyme (EC 2.4. 1. 11.)—rate‐limiting for glycogen synthesis—has previously been investigated in vivo. In the present study this influence was studied in vitro, where interference of epinephrine and insulin on the the effects of contraction is more easily excluded. Electrically stimulated intact levator ani muscle preparations from prepubertal rats were used (Arvill, Acta endocr. 1967. 56. suppl. 122). Glycogen content decreased during 15 min of intermittent tetanization (10 slmin). There was no change in synthetase activity during the contractions. For the period following contractions an increase in the per cent active I‐form of the enzyme was found after 1, 2, 10 and 180 min. Resynthesis of glycogen was shown after 30–180 min. An inverse relation between % I‐form and glycogen content was found when data from 1–10 min after contractions were plotted together with the data from unstirnulated muscles. During repeated single twitches (1/s) for 60 min there was an enhanced penetration of xylose‐14C and a higher rate of incorporation of glucose‐14C into glycogen compared to control muscles. The present results are in good agreement with those previously obtained in vivo. Thus, the influence of contractions in vivo could be demonstrated also in vitro.

EFFECTS OF INSULIN ON THE INTACT LEVATOR ANI MUSCLE OF THE RAT

ABSTRACT The effects of insulin on the rate of intracellular accumulation and incorporation into the protein of some normal amino acids (glycine-3H, leucine-14C and valine-14C) in the intact levator ani muscle of the rat were studied in vitro. The effect of puromycin on the accumulation of these amino acids as well as on the accumulation of the model amino acid α-aminoisobutyric acid-14C (AIB-14C) was examined. In addition the effect of insulin on the incorporation of adenine-14C into the muscle RNA as well as on the effect of actinomycin D added to the incubation medium were also investigated. The insulin stimulated AIB-14C transport is described by the formulation of Michaelis-Menten and approximate values of Km and Vmax are calculated for this transport in the levator ani muscle. Insulin was found to stimulate the intracellular accumulation of glycine-3H and AIB-14C, while a significant decrease was found in the accumulation of leucine-14C and valine-14C. Insulin also stimulated the incorporation of glycine-3H and leucine-14C into the muscle protein. When puromycin was added to the medium, no radioactivity was found in the protein fraction and insulin then stimulated the intracellular accumulation of glycine-3H, leucine-14C and AIB-14C. A slight but significant stimulation with insulin was found on the incorporation of adenine-14C into the RNA-fraction of the levator ani muscle. The addition of actinomycin D was found to inhibit this effect of insulin, but did not change the insulin stimulation of the AIB-14C accumulation. The results are discussed in relation to our present knowledge of the different in vitro effects of insulin.

EFFECTS OF INSULIN ON THE INTACT LEVATOR ANI MUSCLE OF THE RAT

ABSTRACT Effects of insulin in vitro on the rate of intracellular accumulation of α-aminoisobutyric acid (AIB) and D-xylose were studied in the intact levator ani muscle prepared as described by Arvill &amp; Ahrén (1966 a). In some of the experiments the effects of insulin were also studied in the intact diaphragm preparation of Kipnis &amp; Cori (1957). Insulin increased the rate of uptake of AIB and D-xylose in both preparations. A linear dose-response relationship was found within certain dose levels of insulin for the AIB transport in the levator ani preparation. The sensitivity to insulin of the AIB transport was found to be greater in summer than in winter. Addition of glucose to the incubation medium decreased the rate of penetration of D-xylose into the levator ani muscle but it did not influence the rate of AIB uptake or the effect of insulin on the AIB transport. A rapid reduction of the insulin activity in the incubation medium was found in the experiments with the diaphragm preparation but not in the experiments with the levator ani muscle. Insulin was found to cause a flux of water from the extracellular to the intracellular compartments in the diaphragm but not in the levator ani muscle. The results are discussed and it is concluded that the intact levator ani preparation is very suitable for further experiments concerning the mechanism of action of insulin.

Stimulation by insulin of accumulation and incorporation into protein of l-[ 3H]proline in the intact levator ani muscle from the rat

Stimulation by insulin of accumulation and incorporation into protein of l-[ 3H]proline in the intact levator ani muscle from the rat

Insulin-like activity and insulin-inhibitory effect of human albumin fractions studied with two biological test methods.

Human albumin prepared by two different procedures from the blood of seven normal persons and three diabetic subjects has been tested in two biological systemsin vitro, namely the glucose uptake of the rat diaphragm and the distribution of α-amino-iso-butyric acid in the intact levator ani muscle of immature male rats.-Albumin fractions prepared by the trichloroacetic acid-ethanol procedure as it has been used byVallance-Owen et. al. (1958) showed in some cases an insulin antagonistic activity whereas other fractions did not show any insulin antagonism.-Albumin prepared as described byMichael (1962) constantly showed a high insulin-like activity but no antagonism. To some of these albumin fractions a specific anti-insulin serum was added, which partly reduced the insulin-like activity found in these preparations.-The two different assay systems used were found to give closely parallel results, which indicates that the source of conflicting findings probably resides in the steps of the procedure before the assay and not in the assay itself.-The results are discussed in connection to the theories put forward byVallance-Owen and co-workers.